Observations of solar eclipses date back to at least 2500 BC, with ancient civilizations using the events to establish calendars and organize the planting and harvesting of crops. And though most early calendars were lunar calendars, ancient civilizations kept track of how the lunar and solar calendars merged together in events similar to the one we are about to experience today.

Following, 5 ancient civilizations and how they observed their eclipses:

1. The Islamic World:

Islamic astronomy influenced the western world's scientific research during the 9th and 10th centuries AD. Around 825 AD, Al-Khwarazmi (who was known as "Algorizm") developed the first tables trigonometric functions which remained the standard reference well into the modern era, originating the term 'algorithm'.

2. Greece:

By 450 BC, the historian Herodotus (ca 460 BC) mentions that Thales was able to predict the year when a total solar eclipse would occur. Thales is said to have visited Egypt, and from the empirical rules in use there for land surveying, brought back to Greece the ideas of deductive geometry later codified by Euclid.

3. China:

By 2300 BC, Chinese astrologers already had sophisticated observatory buildings from which they observed total solar eclipses in order to forecast the future health and successes of the Emperor. Astrologers were also supposed predict when these events might occur, with failure to do so resulting in beheading of the astrologers.

4. Egypt:

Though the Great Library in Alexandria was burned during the time of Cleopatra and Julius Caesar (destroying an estimated 400,000 books on Egyptian secular literature, mathematics, medicine, and astronomy) temple and pyramid alignments and several papyrus codices suggest a sophisticated knowledge of astronomy and solar eclipses.

5. The Mayans:

Mayan observers also worked on calendars and recorded celestial observations, with “The Dresden Codex” recording several tables thought to be lunar eclipse tables. As in previous civilizations in other parts of the world, the Mayas used records of historical lunar eclipses to calculate how often they occurred over a 405-month period.